Safing and arming mechanism for hand-held munition

ABSTRACT

A safing and arming mechanism for hand-held munitions is disclosed. The safing and arming mechanism is incorporated in a fuze for use in hand grenade type munitions. The mechanism has but three moving parts which requires proper serial operation of the mechanism to cause arming. A lever must be actuated before a safing and arming bolt can be moved from a safing position to the arming position. The munition may also be resafed.

United States Patent [191 Webb [ July 3,1973

[ SAFING AND ARMING MECHANISM FOR HAND-HELD MUNlTlON [75] Inventor: George Webb, Richmond, Ind. [73] Assignee: Avco Corporation, Richmond, Ind.

[22] Filed: Sept. 29, 1971 [21] Appl. No.: 184,878

[52 M US. Cl 102/64, l O2/65.4, 102/70 [51] Int. Cl 1 B41l47/10 [58] Field of Search 102/64, 65.4, 65, l02/85.6, 78, 84, 70

[56] References Cited UNITED STATES PATENTS 3,434,421 3/1969 Berlin 102/64 3,498,223 3/1970 Anderson 102/64 6/1940 Hines ..102/64 3/1948 Peterson ..102/85.6

Primary Examiner-Benjamin A. Borchelt Assistant Examiner-J. V. Doramus Attorney-Charles M. Hogan et a1.

[57] ABSTRACT 10 Claims, 7 Drawing Figures PMENIEUJULCJ 1m 3.742.855

INVENTOR GEORGE WEBB ATTORNEYS SAFING AND ARMING MECHANISM FOR HAND-HELD MUNITION BACKGROUND OF THE INVENTION This invention relates generally to hand grenades and more particularly to a safing and arming mechanism for use in hand grenades.

Hand grenades are one of the oldest forms of explosive weapons to be used in offensive or defensive combat. Grenades of the prior art have long been considered very dangerous and have accounted for a great many selfdnflicted casualties among the troops. The reasons for this have been the prior design of the safety pin, ring assembly and the safety lever. Upon removal of the safety pin, usually a cotter pin or the like, the firing pin assembly is held in the inactive position by the pressure of the throwers thumb on a safety lever. The soldier is told not to replace the safety pin in order to return the grenade to a safed position. Hence, once the safety pin is removed, the soldier is left with a potentially live grenade which must be disposed of. In addition, the safety pin and ring assembly can easily catch on branches of trees and shrubbery resulting in the removal of the safety pin, thus causing detonation and injury. Further, a grenade may be accidentally dropped after the safety pin has been removed and there is then no way to prevent the detonation of the armed grenade. Accordingly, it is an object of this invention to provide a sating and arming mechanism which is reliable in operation and can be manually positioned either in the unarmed or the armed position at the discretion of the thrower. 7

It is another object of the present invention to provide for the arming of the grenade by the positive action of the user.

It is still another object of the present invention to generate a fuze design which will provide out-of-line detonator safety.

A further object of this invention is to provide a safing and arming mechanism which can be resafed with one hand as easily as it was armed.

SUMMARY OF THE INVENTION This invention provides an improved safing and arming mechanism for use in hand grenades. The safing and arming mechanism is of simple and economical construction, is easy to operate with one hand, and provides for the resafing of the grenade if desired. The safing and arming mechanism requires two distinct motions in a correct sequence to cause arming. A lever must be engaged before the arming and safing bolt can be moved from the safing position to the arming position. If resafing is desired, the bolt is returned to the original position. If detonation is desired, the lever is disengaged to permit arming and initiation of the explosive fuze train.

Other objects, details, uses, and advantages of this invention will become apparent as thefollowing description of the exemplary embodiment thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show a present exemplary embodiment of this invention in which:

FIG. 1 is a front elevation view illustrating a hand grenade utilizing the safing and arming mechanism of this invention, the hand grenade being in the safed position;

FIG. 2 is a side elevational view similar to FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a sectional view taken on line 44 of FIG. 5 showing the safing and arming mechanism in the safed position;

FIG. 5 is a cross-sectional view taken along line 5-S of FIG. 4;

FIG. 6 is a cross-sectional view taken along line 66 of FIG. 7 showing the safing and arming mechanism in the arming position; and

FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIGS. 1 and 2 of the drawings, which illustrate an exemplary embodiment of the improved safmg and arming mechanism of this invention, which is designated generally by the reference numeral 10. The safing and arming mechanism 10 is seen, FIG. 3, to be an integral part of a fuze assembly for a hand grenade. The fuze assembly comprises an outer housing or body 12. The housing 12 is adapted to be mounted in a hand grenade 14 by any suitable means, such as threadable engagement therewith. A gasket 16 provides a seal between the grenade 14 and the housing 12.

A lever 18 is carried by the housing 12. The lever 18 is mounted for rotational movement relative to the housing. The lever 18 has a shaft 20 projected therefrom and to which a cam 22 is secured by any suitable means, such as riveting. An O-ring 24 (FIG. 4) provides a dynamic seal between the shaft 20 and the housing 12. The cam 22 is provided with a cam projection 26 which is used to move delay detonator assembly, designated generally as28. The delay detonator assembly 28 is mated with asafing and arming bolt 30 which is mounted for slidable movement in the housing 12.

The sating and arming bolt 30 is formed with a safing groove 32 and an arming groove 34 as seen in FIGS. 4 and 6. O-rings 36 and 38 provide dynamic seals be tween the bolt 30 and the housing 12. The safmg and arming bolt 30 is provided with an enlarged end at one end and means at the other end, such as a C-clamp or the like 42, to prevent the inadvertent removal of the bolt 30. Hence, the bolt 30 may be moved linearly relative to the housing 12 and such movement is limited by the elements 40 and 42.

As seen in FIG. 3, the delay detonator assembly 28 comprises a shaft 44 which is mounted for sliding movement relative to the housing 12 in a direction perpendicular to the movement of the safing and arming bolt 30. The shaft 44-is formed with an undercut 46 adjacent one end to cooperate with the sat'ing and arming bolt 30 in a manner to be described hereinbelow and a notch undercut 48 which cooperates with the cam projection 26. Any suitable delay. detonator 50 is carried by the other end of the shaft 44. The detonator 5t) includes a primer 52 and a lead 54. The delay detonator assembly 28 is spring-biased by spring 56 mounted about shaft 44. The spring at one end acts against the housing 12 and at'the other end against the delay detonator assembly 28 so that when the bolt 30 has been moved to the arming position, the spring 56 drives the delay detonator assembly 28 into contact with a firing pin 58 which is secured in the housing 12 by any suitable means such as crimping the ends of the housing 12 about the firing pin 58. It should be noted that while the exemplary embodiment herein described illustrates the delay detonator assembly 28 as the driven element and the firing pin as the stationary element, this invention may likewise be constructed having the delay detonator 50 mounted stationary in the housing 12 in the lower position and making the firing pin the element driven by the compression spring 56.

In operation, the safing and arming mechanism 10 is initially in the safed position as seen in FIGS. 4 and 5. In this position, the cam projection 26 is mated with the notch undercut 48 and the notch 46 is in cooperating engagement with the safing groove 32. The cooperative engagement of the notch 46 and the safing groove 32 holds the shaft 44 in the upward position so that the detonator 50 is in spaced relation relative to the firing pin 58. The shaft 44 may not be driven downwardly by the spring 56 due to the engagement of the shaft 44 with the bolt 30. In other words, the groove 32 is not of a dimension which will permit the shaft 44 to move a greater distance than that of the undercut por'tion46. In a similar manner, the bolt 30 may not be moved in a linear directon with the shaft in the position shown in FIG. 5 because the outer periphery of the shaft 30 will engage the shaft 44. When it is desire to arm the grenade, the grenade is gripped in the normal manner with the index finger on the lever 18. The lever 18 is pulled towards the housing 12 which results in a rotation of the cam 22. The cam projection 26 acts against the notch undercut 48 and moves the shaft 44 upwards agains the top of the housing 12 so that the maximum undercut portion 46 is in a plane with the center line of the bolt 30. A storage and shipping safety clasp 60 (FIG. 1) is now removed (clasp 60 may have been previously removed) and the end 40 of bolt 30 is pushed until it comes into contact with the housing 12. This results in a moving of the bolt 30 to the position shown in FIG. 6 which is the functioning or arming position of the mechanism 10. In this position, the arming groove 34 has been brought into alignment with the shaft 44. The greater cutaway of groove 34 permits the shaft 44 to slide without impediment relative to the bolt 30. If it is desired to resafe the grenade before release of the lever 18, it is only necessary to move the bolt 30 back to the position shown in FIG. 4 wherein the safing groove is in alignment with the shaft undercut 46. The lever 18 may then be released and the grenade remains in the safed position of FIGS. 4 and 5. However, if it is desired to utilize the grenade, with the bolt 30 in the position of FIG. 6, the lever 18 is released. The spring 56 then drives the delay detonator assembly 28 into engagement with the firing pin 58 as shown in FIG. 7. The engagement of the firing pin 58 with primer 52 initiates the explosive fuze train. At the end of the desired delay time, the lead 54 is detonated causing the detonation of the payload, i.e., high explosive, illuminating or smoke generating agents, etc., of the grenade. It is seen that the spring 56 used to initiate the delay detonator assembly 28 also brings the lead 54 of the delay detonator 50 in alignment with boosters 62, secured in the housing 12, so that the final arming of the explosive fuze train takes place when the grenade is thrown or the lever released.

Safe arming is assured by using a mechanism that requires two distinct operations on the part of the user.

To arm the fuze, the user must first pull the lever before the safing and arming bolt can be moved from the safed position. Reliability is assured by using only three moving parts and is further enhanced by using rugged construction in the critical areas. The human factors aspect has been given considerable thought in this invention. The lever is placed so that the direction of pull is toward the palm. The lever can be operated with the user wearing arctic mittens, and the lever must be moved approximately 54 inch before the safing and arming bolt can be moved. The bolt 30 must be moved approximately inch after the lever is pulled in order to reach the armed position. The lever is near the center of the fuze so that operation can be with either hand. The safing and arming bolt can be moved with the thumb. Thus, arming of the fu ze can be accomplished with one hand. The net result is a fuze which requires two distinct operations in correct sequence, a fuze that requires meaningful motions, a fuze that can be used with either hand, and a fuze that can be armed with one hand. If deployment does not take place, the arming bolt can be returned to the safed position and the lever can be safely released. The above mentioned desirable results are a direct accomplishment of the novel safing and arming mechanism of this invention. Accordingly, the objectives hereinbefore set forth have been accomplished.

While a present exemplary embodiment of this invention has been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced by those skilled in the art.

What is claimed is:

1. A safing and arming mechanism for a hand-held munition of the grenade type which includes a delay detonator assembly and a firing pin, said safing and arming mechanism comprising;

a housing as part of the munition;

a safing and arming bolt slidably mounted in said housing, said bolt having a safing position and an arming position; shaft slidably mounted in said housing transverse said bolt in mating relationship with said bolt, said shaft being interlocked in a first position against sliding movement by said bolt when said bolt is in the safing position, said shaft conversely preventing movement of said bolt from the safing position to the arming position when said shaft is in the first position;

means mounted in said housing and engagable with said shaft for moving said shaft from the first position and retaining said shaft in a second position, the second shaft position freeing said bolt for movement from the safing position to the arming position wherein said shaft is not restricted by said bolt, and following the release of said retaining means;

means for driving said shaft from the second position to a functioning position wherein an explosive fuze train is initiated clue to the relative movement between the delay detonator and the firing pin occasioned by the driving of said shaft from the second position to the functioning position.

2. The mechanism as set forth in claim 1 in which said safing and arming bolt includes an arming groove and a safing groove formed therearound, said arming groove being greater than said safing groove, said safing groove cooperatively mating with said shaft when said bolt is in the safing position and said arming groove cooperatively mating with said shaft when said bolt is in the arming position.

3. The mechanism as set forth in claim 2 in which said shaft is formed with an undercut adjacent one end, said undercut portion cooperating with said bolt safing groove to lock the grenade in the safed position when said shaft is in its first position and when said shaft is in the second position, said shaft undercut portion permitting movement of said bolt from the safing position to the arming position and conversely from the arming position to the safing position whereby the grenade may be resafed so long as said shaft is retained in the second position.

4. The mechanism as set forth in claim 3 in which said moving means includes a lever pivotally mounted in said housing, a cam secured to said lever for rotation therewith, said cam having a cam projection extending outwardly therefrom; and in which said shaft is formed with a notch undercut for receiving said cam projection wherein rotation of said lever causes said cam projection to move said shaft from the first position to the second position wherein said bolt may be moved from the safing position to the arming position, said lever may also be rotated so that said cam projection does not restrict the motion of the shaft.

5. The safing and arming mechanism as set forth in claim 4 in which the delay detonator is secured to the other end of said shaft, and in which said driving means is a spring mounted about said shaft, said spring acting at one end against said housing and at the other end against said delay detonator wherein said spring drives said delay detonator to the functioning position when said bolt is in the arming position and said lever is rotated so as not to restrict the motion of the shaft.

6. The safing and arming mechanism as set forth in claim 5 in which said delay detonator cannot initiate an in-line explosive train in said positions one and two whereas the explosive train is moved to be in-line in the functioning position only.

7. A fuze for arming a munition comprising:

an elongated cylindrical fuze body adapted for mounting with the munition and extending an axial distance within the munition, a firing pin in said fuze body;

a detonator assembly including a primer in said fuze body in spaced axial relation to said firing pin in the safing position;

a shaft mounted in said fuze body for axial movement therealong;

a safing and arming bolt mounted in said fuze body transverse said shaft axis, said bolt having a safing position in which said shaft is prevented from axial movement inwardly of the munition and an arming position in which said shaft is permitted axial movement inwardly of the munition;

said shaft and said bolt jointly cooperating when said bolt is in the safing position wherein said shaft is maintained in a first position and whereby said joint cooperation interlocks said bolt in the arming position;

means for moving said shaft to and retaining said shaft in a second position wherein said bolt is movable to the arming position whereby axial movement of said shaft is unimpeded by said bolt when said means is disengaged, and following the release of said retaining means;

means for driving said shaft from the second position to a functioning position such that the detonator and tiring pin are brought into contact one with the other to initiate an explosive train.

8. A fuze as set forth in claim 7 in which the explosive train is out-of-line in said first and second positions but is brought into line only when said shaft is moved to the functioning position.

9. The fuze as set forth in claim 7 in which said shaft is formed with an undercut adjacent one end thereof and in which said bolt is provided with a safing groove and an arming groove, said shaft undercut portion and said bolt safing groove cooperating in the safing position wherein said shaft and bolt are only permitted limited axial movement one to the other when said shaft is in said first position while said shaft will permit movement of said bolt from the safing to the arming position and vice versa, when said shaft is in the second position, and wherein said shaft undercut portion and said bolt arming groove are in alignment in the arming position, said arming groove being of a dimension which permits movement of said shaft.

10. A fuze as set forth in claim 9 in which said shaft moving means is a lever rotatably mounted to said fuze body, a cam securedly mounted to said lever, said cam having a projection protruding therefrom, and in which said shaft is formed with a notch undercut for receiving said cam projection wherein rotation of said lever causes said cam projection to move said shaft from the first position and retained in the second position whereby said bolt may be moved relative to said shaft, said lever may also be rotated so that said cam projection does not obstruct the motion of said shaft. 

1. A safing and arming mechanism for a hand-held munition of the grenade type which includes a delay detonator assembly and a firing pin, said safing and arming mechanism comprising: a housing as part of the munition; a safing and arming bolt slidably mounted in said housing, said bolt having a safing position and an arming position; a shaft slidably mounted in said housing transverse said bolt in mating relationship with said bolt, said shaft being interlocked in a first position against sliding movement by said bolt when said bolt is in the safing position, said shaft conversely preventing movement of said bolt from the safing position to the arming position when said shaft is in the first position; means mounted in said housing and engagable with said shaft for moving said shaft from the first position and retaining said shaft in a second position, the second shaft position freeing said bolt for movement from the safing position to the arming position wherein said shaft is not restricted by said bolt, and following the release of said retaining means; means for driving said shaft from the second position to a functioning position wherein an explosive fuze train is initiated due to the relative movement between the delay detonator and the firing pin occasioned by the driving of said shaft from the second position to the functioning position.
 2. The mechanism as set forth in claim 1 in which said safing and arming bolt includes an arming groove and a safing groove formed therearound, said arming groove being greater than said safing groove, said safing groove cooperatively mating with said shaft when said bolt is in the safing position and said arming groove cooperatively mating with said shaft when said bolt is in the arming position.
 3. The mechanism as set forth in claim 2 in which said shaft is formed with an undercut adjacent one end, said undercut portion cooperating with said bolt safing groove to lock the grenade in the safed position when said shaft is in its first position and when said shaft is in the second position, said shaft undercut portion permitting movement of said bolt from the safing position to the arming position and conversely from the arming position to the safing position whereby the grenade may be resafed so long as said shaft is retained in the second position.
 4. The mechanism as set forth in claim 3 in which said moving means includes a lever pivotally mounted in said housing, a cam secured to said lever for rotation therewith, said cam having a cam projection extending outwardly therefrom; and in which said shaft is formed with a notch undercut for receiving said cam projection wherein rotation of said lever causes said cam projection to move said shaft from the first position to the second position wherein said bolt may be moved from the safing position to the arming position, said lever may also be rotated so that said cam projection does not restrict the motion of the shaft.
 5. The safing and arming mechanism as set forth in claim 4 in which the delay detonator is secured to the other end of said shaft, and in which said driving means is a spring mounted about said shaft, said spring acting at one end against said housing and at the other end against said delay detonator wherein said spring drives said delay detonator to the functioning position when said bolt is in the arming position and said lever is rotated So as not to restrict the motion of the shaft.
 6. The safing and arming mechanism as set forth in claim 5 in which said delay detonator cannot initiate an in-line explosive train in said positions one and two whereas the explosive train is moved to be in-line in the functioning position only.
 7. A fuze for arming a munition comprising: an elongated cylindrical fuze body adapted for mounting with the munition and extending an axial distance within the munition, a firing pin in said fuze body; a detonator assembly including a primer in said fuze body in spaced axial relation to said firing pin in the safing position; a shaft mounted in said fuze body for axial movement therealong; a safing and arming bolt mounted in said fuze body transverse said shaft axis, said bolt having a safing position in which said shaft is prevented from axial movement inwardly of the munition and an arming position in which said shaft is permitted axial movement inwardly of the munition; said shaft and said bolt jointly cooperating when said bolt is in the safing position wherein said shaft is maintained in a first position and whereby said joint cooperation interlocks said bolt in the arming position; means for moving said shaft to and retaining said shaft in a second position wherein said bolt is movable to the arming position whereby axial movement of said shaft is unimpeded by said bolt when said means is disengaged, and following the release of said retaining means; means for driving said shaft from the second position to a functioning position such that the detonator and firing pin are brought into contact one with the other to initiate an explosive train.
 8. A fuze as set forth in claim 7 in which the explosive train is out-of-line in said first and second positions but is brought into line only when said shaft is moved to the functioning position.
 9. The fuze as set forth in claim 7 in which said shaft is formed with an undercut adjacent one end thereof and in which said bolt is provided with a safing groove and an arming groove, said shaft undercut portion and said bolt safing groove cooperating in the safing position wherein said shaft and bolt are only permitted limited axial movement one to the other when said shaft is in said first position while said shaft will permit movement of said bolt from the safing to the arming position and vice versa, when said shaft is in the second position, and wherein said shaft undercut portion and said bolt arming groove are in alignment in the arming position, said arming groove being of a dimension which permits movement of said shaft.
 10. A fuze as set forth in claim 9 in which said shaft moving means is a lever rotatably mounted to said fuze body, a cam securedly mounted to said lever, said cam having a projection protruding therefrom, and in which said shaft is formed with a notch undercut for receiving said cam projection wherein rotation of said lever causes said cam projection to move said shaft from the first position and retained in the second position whereby said bolt may be moved relative to said shaft, said lever may also be rotated so that said cam projection does not obstruct the motion of said shaft. 